import java.util.Scanner;

public class c4 {
    //编写方法，计算圆的面积和周长，在main方法中接收圆的半径，在自定义方法中计算并输出
    //有参数没有返回值
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入圆的半径：");
        double r = scanner.nextDouble();
        zhouchang(r);
        mianji(r);
    }public  static void  mianji(double r) {

        double s = r * r * 3.14;
        System.out.println("圆的面积：" + s);
    }
    public  static void zhouchang(double r){
        double c=2*r*3.14;
        System.out.println("圆的周长："+c);

    }

}
